1. Field of the Invention
The present invention relates to a setup gage. More specifically, the present invention relates to a setup gage to facilitate a machine set-up for testing hypoid gears in both above and below center hypoid gear arrangements.
2. Description of Related Art
Hypoid gears and pinion gears are machined with very strict tolerances. In order to determine whether the tolerances between the drive pinion gear and the hypoid gear are acceptable, a gear tester and lapper is used to test the gear set as is known in the art. Because hypoid gears and pinion gears vary in size, various combinations of varying size gears require that the gear tester and lapper be properly positioned for a given array of gears.
Thus, prior to testing the actual hypoid (or ring) gear and drive pinion gear, the gear tester and lapper must be properly calibrated with the appropriate distances. Because hypoid gear set uses a hypoid gear that meshes with a drive pinion gear either below or above the centerline of the pinion gear (thus the pinion gear will engage the hypoid gear either above its centerline or below its centerline depending on the application environment) an environment specific set-up gage is required to properly position the gear tester and lapper prior to testing the actual drive pinion gear and ring gear. Because of the various combinations of hypoid gear and pinion gear arrays, several set-up gages must be maintained within an inventory, one set-up gage for each array. Once an array is chosen, it must further be determined whether the hypoid gear will be positioned above the centerline of the pinion shaft, or below the centerline. Hereagain a separate set-up gage is required to position the lapper and gear tester for each arrangement where the pinion gear engages the hypoid gear above and below centerline Once the particular arrangement is identified a set-up gage specifically designed for either above or below centerline applications is employed. The set-up gage is placed within the gear tester and lapper. The simulated hypoid gear is then positioned relative the pinion stem by the faces of the set-up gage""s body. The set-up gage is designed to represent the drive pinion gear, and together with the simulated hypoid gear the actual gear set is simulated and the tester and lapper are positioned/calibrated to test the specific gear set arrangement. Once the critical relative distances have been determined, and the tester and lapper properly calibrated, the simulated hypoid gear and the set-up gage are replaced with the actual hypoid gear and drive pinion gear to be tested. The testing may then commence and the tolerances of the hypoid gear and drive pinion gear measured.
The prior art includes a set-up gage 100 for use with a hypoid gear tester as best seen in FIGS. 1-3. The set-up gage includes a pinion stem 110 with a series of precision ground, polished surfaces 120. The surfaces 120 allow the gage 100 to seat on precision ground surfaces of the tooling collet when inserted within the hypoid gear tester and lapper. Affixed to the end of the pinion stem 110 is the set-up gage body 130. The set-up gage body 130 has orthogonal surfaces 140, 150 and 160 used to position the simulated hypoid gear to facilitate subsequent positioning of the gear tester. Pads 140a, 150a, and 160a are secured to the set-up gage""s surfaces 140, 150 and 160 respectively in order to ensure the proper offset distances are used for the simulated hypoid gear 80 and that of the gear tester. Heretofore, separate set up gages were required for applications where the pinion gear engages the hypoid gear above and below the centerline.
Other prior art testing devices include a gear tester method and an apparatus for inspecting the contact area between a hypoid gear and a pinion. The gear tester includes an apparatus for inspecting the contact area between selected tooth surfaces of a spiral bevel or hypoid gear relative to selected gear tooth surfaces of a second gear such as a pinion.
Additionally, it is also known to have a gear testing machine for evaluating the performance of a set of gears. The machine includes a platform for mounting a pinion gear relative to the pinion through actuators attached to a frame so that the gears may be positioned at a desired location relative to the pinion spindle axis to compensate for errors in mounting as well providing accurate mounting in accordance with required mounting criteria.
The aforementioned prior art fails to provide a machine or device to set up the alignment of a gear tester and lapper to accommodate both an above and a below center hypoid gear arrangement with a single set up gage. In the prior art, two separate set up gauges are required to properly set a testing machine for an above center front hypoid gear arrangement as well as a below center rear hypoid gear arrangement. Thus, gage inventory is increased via the necessity of having more than one gage for the multiple arrangements of the hypoid and pinion gears.
Similarly, the cost associated with testing the aforementioned gears also increases, requiring more than one gage to be kept within an inventory. Gages with a single purpose reduce the flexibility of the inventory ultimately rising costs as previously stated.
It is therefore an advantage of the present invention to provide a set-up gage for performing a machine set-up for both above and below the center hypoid gear designs, where the set-up gage includes a gage body and a pinion stem. The pinion stem is integrally attached to the gage body. The gage body provides a first set of surfaces and a second set of surfaces to position a ring gear, or simulated ring gear, relative to the pinion stem. The first set of surfaces is adapted to position the ring gear in an above center hypoid gear design, while the second set of surfaces is adapted to position the ring gear in a below center hypoid gear design.